An efficient computerized decision support system for the analysis and 3D visualization of brain tumor

The quality of health services provided by medical centers varies widely, and there is often a large gap between the optimal standard of services when judged based on the locality of patients (rural or urban environments). This quality gap can have serious health consequences and major implications for patient’s timely and correct treatment. These deficiencies can manifest, for example, as a lack of quality services, misdiagnosis, medication errors, and unavailability of trained professionals. In medical imaging, MRI analysis assists radiologists and surgeons in developing patient treatment plans. Accurate segmentation of anomalous tissues and its correct 3D visualization plays an important role inappropriate treatment. In this context, we aim to develop an intelligent computer-aided diagnostic system focusing on human brain MRI analysis. We present brain tumor detection, segmentation, and its 3D visualization system, providing quality clinical services, regardless of geographical location, and level of expertise of medical specialists. In this research, brain magnetic resonance (MR) images are segmented using a semi-automatic and adaptive threshold selection method. After segmentation, the tumor is classified into malignant and benign based on a bag of words (BoW) driven robust support vector machine (SVM) classification model. The BoW feature extraction method is further amplified via speeded up robust features (SURF) incorporating its procedure of interest point selection. Finally, 3D visualization of the brain and tumor is achieved using volume marching cube algorithm which is used for rendering medical data. The effectiveness of the proposed system is verified over a dataset collected from 30 patients and achieved 99% accuracy. A subjective comparative analysis is also carried out between the proposed method and two state-of-the-art tools ITK-SNAP and 3D-Doctor. Experimental results indicate that the proposed system performed better than existing systems and assists radiologist determining the size, shape, and location of the tumor in the human brain.

     

Effectiveness of crypto-transcoding for H.264/AVC and HEVC video bit-streams

Multimedia Tools and Applications - To avoid delays arising from a need to decrypt a video prior to transcoding and then re-encrypt it afterwards, this paper assesses a selective encryption (SE)...     

Conceivable security risks and authentication techniques for smart devices: A comparative evaluation of security practices

With the rapidly escalating use of smart devices and fraudulent transaction of users data from their devices, efficient and reliable techniques for authentication of the smart devices have become an obligatory issue. This paper reviews the security risks for mobile devices and studies several authentication techniques available for smart devices. The results from field studies enable a comparative evaluation of user-preferred authentication mechanisms and their opinions about reliability, biometric authentication and visual authentication techniques.     

Effect of annealing and oxygenation on the DC conductivity of amorphous germanium

Thin films of amorphous germanium were deposited in an oxygen atmosphere.dc conductivity results are interpreted considering the possibility of the formation of Ge-O bonds. The density of states was determined. Results of conductivity are interpreted using the Davis-Mott model. Change in conductivity in annealed films of V-a-Ge and O-a-Ge is also reported.     

CIRCULATION IN LARGE SCALE JET BUBBLE COLUMNS

A hydrodynamic study in a gas-liquid jet bubble column was undertaken in a column with a 122 cm diameter cylindrical section and a conical bottom section approximately 180cm in height. Due to the jetting action in the cone, the circulation patterns are different from those in cylindrical bubble columns. In order to examine this difference in flow pattern, circulation velocity measurements were undertaken (for V₅ = 0.39-2.73 cm/s and V, = 0-0.044 cm/s) using the Pavlov tube technique. These measurements should be helpful in understanding other design parameters (such as mixing, phase distribution, transport coefficients, etc.). Pressure drops were also measured at nine axial taps and using these values, sectional average gas holdup values were calculated. The study was centered on the conical section; the cylindrical bubble column was assumed to be the limiting case for the interpretation of the data. Using the experimental observations, the height of the jet effective region was approximated by two different methods. A simple empirical correlation to find the centerline velocity is proposed.     

Errors caused by tracer solubility in the measurement of gas phase axial dispersion

Gas phase dispersion studies in bubble columns have been previously analyzed with the axial dispersion model neglecting the solubility of the tracer gas. In the present study, the effect of the solubility of the tracer gas on the accuracy of dispersion measurements is examined using the axial dispersion model with interphase transfer. Expressions for the first and second moments have been derived assuming the liquid phase to be well mixed. These moments are found to be functions of the Stanton number, Peclet number, Henry's constant, ratios of gas to liquid holdups and velocities. It is found that neglecting the interphase transfer can lead to significant deviations from the expected moments, and thus to errors in the Peclet number, even for a relatively insoluble gas like helium in water.     

Solution of final stages of polyethylene terephthalate reactors using orthogonal collocation technique

The formation of polyethylene terephthalate (PET) has been modeled to have reactions with monofunctional compounds, redistribution, and cyclization reactions in addition to the usual polycondensation step. In the final stages, the overall polymerization is mass-transfer controlled and solution of the reactor performance equations have been determined through the orthogonal collocation technique. This technique is found to be considerably more efficient for PET reactors compared to the finite difference method; the use of ten collocation points gives results which are close to the exact solution.     

Prediction of polyethylene melt rheological properties from molecular weight distribution data obtained by gel permeation chromatography

A method is presented for predicting rheological characteristics, such as shear dependent (non-Newtonian) viscosity and components of linear oscillatory (complex) response functions for polyethylene melts from molecular weight distribution data obtained from gel permeation chromatographic (GPC) analysis. The results are compared with measured values of the rheological functions obtained from a variety of instruments over an extensive range of shear rates-and frequencies. The agreement between predicted and measured rheological functions is quite good for high density resins. However, for a low density resin the agreement is not as good, although still reasonable over a considerable range of conditions. It is concluded that the quality of the GPC data is the key factor in the degree of success of the method.